Many computer systems have peripheral ports configured to connect to and interface with peripheral devices. A large portion of such ports implement the Universal Serial Bus (USB) standard. The physical interface specifications of the USB standard allow for a variety of peripheral devices to be connected to a computer using a simple, standardized socket. Hardware peripheral devices that typically use USB or similar peripheral ports include, but are not limited to, external hard drives, keyboards, mice, wireless network adapters, scanners, printers, and the like. USB peripheral ports are typically managed by a host controller, a hardware device that serves as an interface between a computing device and the peripheral devices connected to the USB ports of the computing device. In addition to managing the flow of data between the host computing device and the peripheral devices, the host controller also provides electrical power from the computing device's power supply to the peripheral devices via the USB ports.
One particular advantage of the USB standardization is that it provides for some devices to be powered directly from a USB port. With the increasing ubiquity of the USB standard in modern computing devices, it has become increasingly common for peripheral devices, particularly small battery-powered peripheral devices, to rely on a peripheral device port, such as a USB port, in a host computing device as a principle source of electrical power instead of or in addition to a separate power supply.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.